The present invention relates to a toothbrush provided with adjusting means to control the maximum brushing pressure which may be applied to the teeth during use. Many studies have shown that low brushing pressure results in incomplete removal of dental plaque which acts as a breeding area for cavity-inducing mouth bacteria. Excess pressure on the other hand produces gingival laceration, wear of the enamel, exposure of dentin and subsequent damage such as gingival recession and root exposure. Reliance has been placed on the training of children and adults by dentists and dental hygienists on suitable brushing techniques and on the selection of brushes. Currently recommended brushes have rounded, soft nylon or natural bristles about 0.007 inches in diameter and 12 millimeters long and a density of approximately 3 bristles per square millimeter. Although the use of brushes with these characteristics and the application of recommended techniques represents progress in achieving improved cleaning and limiting abrasive damage, individual differences in brushing pressure tend to produce highly variable results.
Many newer toothbrush concepts have been devised but these have dealt with improvement in brushing efficiency alone. Relatively few of the newer brushes have reflected attempts to regulate the applied pressure. A recent design described in the Journal of Clinical Dentistry, Volume II, No. 4, p 107 of 1991 employs a spring incorporated in the brush handle so that brushing pressure can be more readily monitored by the user (as judged by the amount of flexion). Tests show however that individual differences were still present in judging the optimum pressure to apply.
Other designs have employed specially shaped handles which encourage light gripping--e.g. a "pen grip". The only previously-available effective controls on brushing pressure rely on the provision of hard, medium and soft bristles--or combinations--in individual brushes.
It is one objective of the present invention to provide a linear, flexibly coupled brush and handle which has a "break-away" limit so that pressure in excess of a preset amount causes the handle to move out of the plane of brushing. By maintaining the brush in a useable orientation, the user will automatically maintain the pressure at a value to optimize tooth cleaning and minimize erosive effects.
It is a second objective of the present invention to provide a calibrated adjustability of the break-away pressure so that the setting may be varied to apply to a wide range of individual characteristics.
These and other objectives will be presented in the description and claims given in the following specifications, drawings and claims.